This invention relates to thermoplastic compositions and more particularly to polyphenylene ether resin compositions.
The term "polyphenylene ether resin" includes a family of polymers well known to those skilled in the art. They are made by a variety of catalytic and non-catalytic processes from the corresponding phenols or reaction derivatives thereof. By way of illustration, certain of the following polyphenylene ethers are discussed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875 and in Stamatoff, U.S. Pat. Nos. 3,257,357 and 3,257,358. Also, the Bennett and Cooper patents, U.S. Pat. Nos. 3,639,656, 3,642,699 and 3,661,848 describe processes for the preparation of polyphenylene ethers. In the Hay patents, the polyphenylene ethers are prepared by an oxidative coupling reaction comprising passing an oxygen-containing gas through a reaction solution of a phenol and a metalamine catalyst.
Other disclosures relating to processes using metalamine cataysts are found in Bussink et al, U.S. Pat. No. 3,337,499; Blanchard et al, U.S. Pat. No. 3,219,626; Laakso et al, U.S. Pat. No. 3,342,892; Borman, U.S. Pat. No. 3,344,166; Hori et al, U.S. Pat. No. 3,384,619; Faurote et al, U.S. Pat. No. 3,440,217; and disclosures relating to metal based catalysts which do not include amines, are well known from patents such as Wieden et al, U.S. Pat. No. 3,442,885 (copper amidines); Nakashio et al, U.S. Pat. No. 3,573,257 (metal-alcoholate or phenolate); Kobayashi et al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In the Stamstoff patents, the polyphenylene ethers are produced by reacting the corresponding phenolate ion with an initiator, such as a peroxy acid salt, an acid peroxide, a hypohalite, and the like, in the presence of a complexing agent. Disclosures relating to non-catalytic processes, such as oxidation with lead dioxide, silver oxide, etc., are described in Price et al, U.S. Pat. No. 3,382,212. All of the patents which are mentioned above are incorporated herein by reference.
The Cizek patent, U.S. Pat. No. 3,383,435, discloses compositions of polyphenylene ether resins and styrene resins. The thermoplastic composition disclosed by Cizek may include a rubber-modified styrene resin, as well as crystal polystyrene.
It has now been surprisingly discovered that when the conventional polystyrene and rubber-modified polystyrene resins in these polyphenylene ether compositions are replaced with a copolymer of a vinyl aromatic compound and an .alpha.,.beta.-unsaturated cyclic anhydride, the heat distortion temperature of the polyphenylene ether composition, as well as other physical properties, is dramatically increased.